Collapsible frame sea anchor



. 20, 1949 H. lvl-:RSEN

COLLAPSIBLE FRAME SEA ANCHOR Patented Dec. 20, 1949 COLLAPSIBLE FRAME SEA ANCHOR Hjalmar Ivcrsen, Strandbakke, Nesbryggen, Netteroy, Norway Application November 28, 1945, Serial No. 631,306 In Norway February 18, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires February 18, 1963 4 Claims. (Cl. 114-209) This invention relates to collapsible frame sea anchors of the umbrella type, wherein a canvas web is carried by a plurality of arms each pivotally attached to the rear end of a central bar, and each arm between the pivot point and the exterior end thereof being pivotally attached to the exterior end of a tensioning member, the inner end of which is in turn pivotally attached to a sleeve slidable on the central bar. In such sea anchors the canvas web is tensioned by the water pressure alone acting against the inner side of the umbrella. When therefore the life boat moves backwards and the sea anchor for this reason is towed after the boat with constant jerks, the canvas web may easily collapse. This applies particularly between the wind squalls, because the tow line during these may be repeatedly slack. As a consequence thereof sea anchors of this construction have a low efficiency, and in many cases they have no effect at all.

It is an object of the present invention to avoid these drawbacks by the tow line being attached to the sleeve and passed slidably through a mounting attached to the forward end of the central bar. Thereby is obtained the possibility of locking the anchor against collapsing under the action of the water pressure directed forwards against the outer side of the canvas. This is obtained by arranging an abutment for the slidable sleeve on the central bar in a manner known per se so that the tensioning members,l

when the sleeve has been pulled forwards by the tow line in engagement with the abutment, are as formerly known in an inclined position with their inner ends located more forwards than their exterior ends.

In the drawing the sea anchor is illustrated in a side View, partly in section.

On the forward end of the central bar I a mounting in the form of a sleeve 2 is attached. from which project for instance four wires 3 connected to the exterior end of the anchor arms 4, on which the canvas web 5 is fixed. The arms are at their innermost portions hinged on pivots 6 in a sleeve 'I which is attached to the rear end of the bar I, for instance by means of a nut 8 with hexagonal portion il and screw III.

Somewhat inside the exterior end each arm 4 is hingedly connected by a pivot II wth the exterior end of a tensioning member I2 the inner end of which is hingedly connected by a pivot I3 with a sleeve I4 slidable on the bar I. To the latter are attached for example four wires I5 which are passed slidably forwards and through holes I6 in the sleeve 2, and in front of the same 2 are brought together to a bight or collected in a thimble I'I, wherein the tow line I8 from the life boat is attached. The Wires i5 from the sleeve I 4 are also passed backwards slidably through holes I9 in the sleeve 8, and behind the same collected in a thimble 2i), to which is attached a hauling-in rope 2| which goes back to the boat.

An abutment 22 on the bar I arrests the sleeve I4 in the position illustrated, wherein the pivots I3 are located somewhat forward of the pivots I I, so that the tensioning .members I2 have an inclined, locking position for the arms 4. In this position the anchor as mentioned is locked in tensioned conditon, and water pressure from the rear side against the outer surface of the canvas cannot collapse the umbrella. Moreover the pull in the rope I8 acts to maintain the sleeve Ill in its place in locking position.

When the sea anchor is hauled in by means of rear rope 2|, the anchor is turned around and the thimble 2|) pulls the wires I5 in a direction towards the rear end of the anchor.

Thereby the sleeve Ill is moved backwards on the bar I, the pivots i3 pass beyond the locking position, and the sleeve le finally abuts against the foremost end surface of the rear sleeve I simultaneously as the members I2 pull the arms 4 together to the collapsed position against the bar I.

When the anchor is again to be used, it is tensioned by pulling forwardly on rope i8 and thimble I'I, whereby the seeve I4 again slides forwards to the locking position shown in the drawing.

I claim:

1. Collapsible frame sea anchor for life boats comprising a central bar, a sleeve slidable thereon, a plurality of radial arms pivotally connected with the rear end of the bar, a tensioning member connected pivotally at its outer end to each arm intermediate the ends thereof and at its inner end to said sleeve, a canvas web carried by and extending between said arms, a mounting connected to the forward end of the bar,

' and a tow line attached to the sleeve and passing slidably through the mounting and through the rear end of the bar.

2. A sea anchor according to claim 1, wherein the tow line is in the form of a plurality of wires collected to a thimble bight outside the forward end of the anchor and similarly collected to a thimble bight outside the end of the bar and a mounting connected to the rear end of the bar and provided with holes for sliding passage of the wires, the mountmg connected to the forward end of the bar having corresponding holes outer end, thereby locking the arich'or against collapse under the action of the water pressure directed against the outer surface of the canvas web.

4. A sea anchor according to claim l, wherein the tow line is in the form of a pluralit? of wires collected to a thimble bight outside the forward end of the anchor and similarly collected to a thimble bight outside the rear end of the bar,

and a mounting connected to the rear end of the bar and provided with holes for sliding passage of the wires, the mounting connected to the forward end of the bar having corresponding holes for sliding passage` of the wires, and a sleeve abutment connected to the central bar in 'such a position, that th tensioning Afembers, when the sleeve is pulled forwards by the tow line in engagement with said abutment, take up an inclined position with their inner ends located more forwards than their outer ends, thereby locking the anchor against collapse under the action of the water pressure directed against the outer surface of the canvas web.

HJALMAR IVERSEN.

references cited. 

